Reversible posterior leucoencephalopathy syndrome associated with anticancer drugs

Chemotherapy-Induced Leukoencephalopathy Revealed by Seizure and Alteration of the Mental Status

Leukoencephalopathy is progressive demyelination of the white matter, induced by a variety of factors. Among the causes of leukoencephalopathy, chemotherapy is an uncommon cause that generates potentially reversible lesions. The clinical presentation is classically made of alterations in mental status, hallucinations, hypertension, seizures, and acute visual changes. Imaging plays an important role in the diagnosis of this entity, especially by conventional and diffusion-weighted magnetic resonance imaging which enables an accurate diagnosis by identifying symmetric white matter lesions, especially in the parietal and occipital lobes. Herein, we report a 54-year-old female patient, newly diagnosed with non-metastatic moderately differentiated adenocarcinoma of the cecum. The patient received her first cancer chemotherapy (5-fluorouracil at 300 mg/m²). Five days later she was admitted to the intensive care unit for confusion following two generalized seizures. Conventional and diffusion-weighted magnetic resonance imaging was performed and showed diffuse white matter lesions of the parietal and occipital lobes. A diagnosis of 5-fluorouracil-induced leukoencephalopathy was established. The diagnosis of leukoencephalopathy should be considered in patients receiving cancer chemotherapy with alterations in mental status and seizures.

Uterine sarcoma with posterior reversible encephalopathy syndrome associated with pazopanib

WHAT IS KNOWN AND OBJECTIVE

Our objective is to report on a case of posterior reversible encephalopathy syndrome associated with pazopanib.

CASE DESCRIPTION

A 64-year-old patient with uterine sarcoma developed PRES 3 days after pazopanib was initiated. After the discontinuation of pazopanib, the symptoms of PRES improved.

WHAT IS NEW AND CONCLUSION

The first report worldwide to describe a patient with uterine sarcoma experiencing PRES caused by pazopanib. Patients with uterine sarcoma may experience PRES, even in the early phase of pazopanib therapy.

Posterior Reversible Encephalopathy Syndrome Secondary to Cyclophosphamide

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiological diagnosis defined as new onset seizures, headaches, impaired vision and consciousness. PRES is typically associated with hypertensive emergencies and pre-eclampsia but its association with autoimmune diseases is largely multifactorial with the combination of ongoing immunologic processes, sepsis and cytotoxic agents contributing to patient’s presentation. Cyclophosphamide induced PRES is rare and has been reported in cases of patients with renal failure and active autoimmune processes.

Anti-Angiogenic Tyrosine Kinase Inhibitors and Reversible Posterior Leukoencephalopathy Syndrome: Could Hypomagnesaemia Be the Trigger?

Reversible posterior leukoencephalopathy syndrome (RPLS), also known frequently as posterior reversible encephalopathy syndrome (PRES), is a characteristic acute neuro-radiology syndrome with clinical presentation that typically includes acute hypertension, seizures and other neurological symptoms and signs. Many patients with RPLS have (a history of) pre-existing hypertension and in receipt of diuretics. It is being diagnosed more frequently and in association with an increasing number of morbidities and medications. Drugs most frequently implicated are immunosuppressant drugs and anticancer agents, including a number of anti-angiogenic tyrosine kinase inhibitors (TKIs). Hypomagnesaemia is a frequent finding at presentation in RPLS patients, which is known to lead to or aggravate hypertension. Pre-eclampsia, a variant of RPLS, responds effectively to intravenous magnesium. Cyclosporin, tacrolimus and some TKIs that induce RPLS are also known to give rise to both hypertension and hypomagnesaemia. This raises an interesting hypothesis that hypomagnesaemia may play a contributory role in triggering RPLS in some patients by acutely raising the blood pressure further. Additional systematic studies are required to test this hypothesis. If the hypothesis is confirmed, hypomagnesaemia offers an effective target for risk mitigation and prevention of RPLS in patients identified at risk.

Posterior reversible encephalopathy syndrome (PRES) induced by pazopanib, a multi-targeting tyrosine kinase inhibitor, in a patient with soft-tissue sarcoma: case report and review of the literature

Posterior reversible encephalopathy syndrome (PRES) is a clinical entity characterized by acute neurological symptoms such as severe headache, seizures, and visual disturbance, and by typical reversible lesion on brain magnetic resonance (MR) images. Since PRES is thought to be caused by vascular endothelial injury due to cytotoxic agents or acute systemic hypertension, the number of reports on PRES associated with angiogenesis inhibitors has been increasing. Although five cases that developed PRES due to pazopanib for renal cell carcinoma have already been reported, none of PRES due to pazopanib for soft-tissue sarcoma has been reported thus far. We describe a case of a 49-year-old woman with retroperitoneal soft-tissue sarcoma who developed PRES during pazopanib administration. Pazopanib at 800 mg/day was administered as her third-line treatment at relapse. After 38 days of pazopanib, she was admitted to our hospital with severe headache, vomiting, and systemic hypertension. The next day, she developed consciousness deterioration and visual disturbance together with exacerbated systemic hypertension. Brain MR images revealed hyper-intense signals on FLAIR sequences in the bilateral occipital lobes and the left thalamus. Intravenous nicardipine injection was immediately started to control her blood pressure and pazopanib was discontinued. Her symptoms gradually improved and disappeared on the fifth hospital day. After 2 weeks, hyper-intense signals on a FLAIR sequence disappeared completely. She restarted a low dose of pazopanib under good blood pressure control and experienced no subsequent recurrence of PRES.

Sorafenib-induced reversible posterior leukoencephalopathy in patients with renal cell carcinoma: A report of two cases

Reversible posterior leukoencephalopathy syndrome (RPLS) is a rare clinicoradiological syndrome that is characterized by neurological symptoms, including seizures, headaches, visual abnormalities, confusion and encephalopathy, accompanied by vasogenic edema of the posterior white matter observed on neuroimaging. Sorafenib is an inhibitor of pro-angiogenic receptor tyrosine kinases, such as vascular endothelial growth factor receptor 2, platelet-derived growth factor receptor β, and vascular endothelial growth factor receptor 3. In the previous research literature, only one case of sorafenib-induced RPLS, in a patient with hepatocellular carcinoma, has been reported. The current report presents two cases of sorafenib-induced RPLS in patients with metastases from a renal cell carcinoma. In the first case, a 75-year-old female patient developed a fever, fell down and was unable to move her limbs as instructed after 11 days of sorefenib treatment. Brain magnetic resonance imaging (MRI) demonstrated no typical RPLS findings. As all of the symptoms were resolved after sorafenib discontinuation, sorafenib was restarted. However, the patient remained unable to walk steadily and to articulate properly after 10 days. MRI again demonstrated no notable findings, and her condition improved only after discontinuation of the sorafenib. In the second case, a 75-year-old male patient experienced a fall due to loss of consciousness. T2-weighted and fluid-attenuated inversion recovery MRI revealed high-intensity signals on both sides of the cerebellar hemisphere and pons, and also partially on both sides of the frontal lobe. At 33 days after sorafenib discontinuation, he had recovered sufficiently to walk by himself with a walker, and a repeat MRI revealed a significant improvement. Although one case took a longer time, both cases were fortunately reversible by discontinuation of sorafenib treatment and administration of combined-modality therapy (including oxygen, steroids, verapamil, digoxin and nicardipine hydrochloride). The oncology community should be alerted to this uncommon and life-threatening adverse event.

Kinase inhibitors and monoclonal antibodies in oncology: clinical implications

Molecularly targeted cancer therapies, such as small-molecule kinase inhibitors and monoclonal antibodies, constitute a rapidly growing and an important part of the oncology armamentarium. Unlike conventional (cytotoxic) chemotherapeutics, targeted therapies were designed to disrupt cancer cell pathogenesis at specific biological points essential for the development and progression of the tumour. These agents were developed to disrupt specific targets with the aim of minimizing treatment burden compared with conventional chemotherapy. Nevertheless the increasingly common use of targeted therapies has revealed some unanticipated, often clinically significant toxic effects, as well as compromising effective palliative and end-of-life management approaches. Although patients and clinicians welcome improvements in cancer prognosis, these changes can also impact patient quality-of-life. Therefore, as demand for oncology expertise increases, physicians need to apprise themselves of targeted therapies and their clinical implications, including drug-specific side effects, impact on quality of life, and cost issues, especially in relation to end-of-life care. This Review provides a useful summary and guide for professionals treating patients with malignant diseases.

Fatal posterior revesible leukoencephalopathy syndrome associated coma induced by bevacizumab in metastatic colorectal cancer and review of literature

Posterior reversible leukoencephalopathy syndrome (PRES) is a syndrome characterized by headache, hypertension, confusion, visual disturbance, and seizures accompanied by subcortical vasogenic edema, predominantly involving the parietal and occipital lobes. The syndrome is usually described in malignant hypertension, eclampsia, renal failure, immunosuppressive, and cytotoxic chemotherapies. Bevacizumab, a monoclonal antibody that binds to the vascular endothelial growth factor (VEGF) has been linked to PRES. We carried out review of reports documenting the occurrence of PRES in patients receiving bevacizumab. This literature review was conducted by utilizing PubMed Database. If early diagnosed, PRES is reversible. We present a case of fatal PRES-associated coma induced by bevacizumab in metastatic colorectal cancer.

Posterior reversible encephalopathy syndrome induced by enzalutamide in a patient with castration-resistant prostate cancer

Posterior reversible encephalopathy syndrome (PRES) is a clinical/radiological syndrome characterized by symptoms that can include seizure, headache, impaired vision and hypertension, and can be confirmed by magnetic resonance imaging. Numerous reports have emerged that describe PRES in cancer patients. The list of medications linked to PRES can include traditional cytotoxic chemotherapeutics (e.g., cisplatin, cyclophosphamide, and high-dose corticosteroids), newer agents that target the vascular endothelial growth factor pathway (e.g., bevacizumab, sunitinib, and pazopanib), and supportive care mediations (e.g., granulocyte colony stimulating factors and erythropoietin). We report, for the first time, a case of PRES that is secondary to treatment with enzalutamide, a potent androgen receptor antagonist used in the treatment of metastatic castration-resistant prostate cancer. Enzalutamide is approved for the treatment of both docetaxel-pretreated and chemotherapy-naïve metastatic castration-resistant prostate cancer. Enzalutamide has been previously linked to the increased risk of seizures. Clinicians should be aware that, in rare cases, patients treated with enzalutamide could potentially be at risk for PRES. If symptoms suggestive of PRES arise in patients receiving enzalutamide, the drug should be discontinued immediately and the diagnostic process should be initiated.

Small-animal PET demonstrates brain metabolic change after using bevacizumab in a rat model of cerebral ischemic injury

To evaluate the effect of bevacizumab on cerebral ischemia, we used 2-deoxy-2-(18)F-fluoro-D-glucose ((18)F-FDG) small-animal positron emission tomography (PET) in the middle cerebral artery occlusion (MCAO) rat model. After baseline neurologic function tests and PET studies, MCAO Sprague-Dawley rats received bevacizumab or normal saline (controls). Weekly PET imaging and neurologic function tests showed that the (18)F-FDG accumulation in the bevacizumab group was similar to that in the controls during the first 2 weeks, but lower than in controls at weeks 3 and 4. However, no difference was found in neurological scores between the groups. The number of von Willebrand factor-positive cells in the bevacizumab group was lower than that in controls. The expression of vascular endothelial growth factor was higher than in controls at week 4. These results suggested that bevacizumab does not influence functional recovery in this model of cerebral ischemia during a 4-week period, but inhibits vascular formation and metabolic recovery, which may be considered in cancer patients with a recent ischemic stroke.

Bortezomib-induced posterior reversible encephalopathy syndrome: clinical and imaging features

Posterior reversible encephalopathy syndrome (PRES) is a rare and potentially harmful complication in patients receiving targeted chemotherapy. We herein present a case of PRES that occurred after 33 days of high-dose bortezomib treatment and propose both overwhelmed cerebral autoregulation and toxin-mediated blood-brain barrier damage as the underlying mechanisms based on the imaging findings. A favorable recovery was observed two days after achieving stringent hypertension control and withholding bortezomib. Follow-up images obtained two weeks later unveiled a dramatic remission, with faint areas of subcortical hyperintensity in the bilateral parieto-occipital regions. With explicit clinical and imaging features, this case highlights the need for early recognition of PRES during the clinical course of bortezomib therapy.

A phase II multicentre study of ziv-aflibercept in combination with cisplatin and pemetrexed in patients with previously untreated advanced/metastatic non-squamous non-small cell lung cancer

BACKGROUND

This study evaluated the efficacy and safety of ziv-aflibercept in combination with cisplatin and pemetrexed in non-small cell lung cancer (NSCLC).

METHODS

This single arm, multicentre phase II trial enrolled patients with previously untreated, locally advanced or metastatic non-squamous NSCLC. Patients received intravenous ziv-aflibercept 6 mg kg(-1), pemetrexed 500 mg m(-2), and cisplatin 75 mg m(-2), every 21 days for up to six cycles. Maintenance administration of ziv-aflibercept was to continue until disease progression, intolerable toxicity or other cause for withdrawal. The co-primary end points were objective response rate (ORR) and progression-free survival (PFS). Planned sample size was 72 patients.

RESULTS

The study was closed prematurely because of three confirmed and two suspected cases of reversible posterior leukoencephalopathy syndrome (RPLS). A total of 42 patients were enrolled. Median age was 61.5 years; 55% were male, 86% Caucasian and 50% had Eastern Cooperative Oncology Group performance status (ECOG PS)=0. A median of four cycles of ziv-aflibercept was administered. The most common treatment-emergent adverse events (TEAEs) of any grade were nausea (69%) and fatigue (67%), with hypertension (36%) as the most common grade 3/4 TEAE. Of the 38 evaluable patients, ORR was 26% and median PFS was 5 months.

CONCLUSION

Cases of RPLS had been observed in other studies in the ziv-aflibercept clinical development programme but the rate observed in this study was higher than previously observed. This might be related to declining renal function and/or hypertension. Although ORR and PFS were in accordance with most historical first-line NSCLC studies, this combination of ziv-aflibercept/cisplatin/pemetrexed will not be further explored in NSCLC.

A phase II evaluation of motesanib (AMG 706) in the treatment of persistent or recurrent ovarian, fallopian tube and primary peritoneal carcinomas: a Gynecologic Oncology Group study

OBJECTIVES

Vascular endothelial growth factors (VEGF) and their receptors have a critical role in stimulating the growth of ovarian cancer cells. Motesanib is a small molecule inhibitor of multiple receptor tyrosine kinases including VEGF receptors 1-3, as well as c-KIT and platelet-derived growth factor which are related to the VEGF family.

PATIENTS AND METHODS

Twenty-two eligible patients with recurrent ovarian, fallopian tube or primary peritoneal carcinoma were treated with an oral daily dose of 125 mg of motesanib. Peripheral blood was analyzed for circulating tumor cells (CTC) and circulating endothelial cells/circulating endothelial progenitors (CEC/CEP), VEGF levels and cell-free circulating DNA (cfDNA).

RESULTS

The study was abruptly halted after four patients developed posterior reversible encephalopathy syndrome. One patient had a partial response and seven patients had stable disease at the time they were removed from study treatment. Twelve of the 22 patients (50%) had indeterminate responses at trial closure. Early closure without clinical efficacy data precludes meaningful correlative studies.

CONCLUSIONS

The serious central nervous system toxicity observed in patients with recurrent ovarian cancer precluded full examination of this agent in this population. There were no clear cut explanations for the high incidence of this known class effect in the study population compared with patients with other cancers.

Reversible posterior leukoencephalopathy syndrome associated with concurrent bevacizumab, gemcitabine, and oxaliplatin for cholangiocarcinoma

INTRODUCTION

Reversible posterior leukoencephalopathy syndrome (RPLS) is a rare disorder characterized by altered mental status, seizure, hypertension, and symmetrical white matter edema (leukoencephalopathy) typically in the posterior cerebral hemispheres on brain imaging. It is often linked to certain medication use, in particular, chemotherapeutic agents. Here, we present a case of chemotherapy-related RPLS and review the current literature on this topic.

CASE REPORT

We report a case of RPLS associated with concurrent bevacizumab (Avastin), gemcitabine, and oxaliplatin use for unresectable intrahepatic cholangiocarcinoma.

CONCLUSION

This is the first reported case of RPLS associated with bevacizumab, gemcitabine, and oxaliplatin combination chemotherapy. Concurrent use of multiple agents could significantly increase the risk of RPLS, a potentially fatal disease. Our case suggests that gradual progression of hypertension and proteinuria may be early warning signs before the onset of RPLS that should alarm clinicians.

Early changes in brain FDG metabolism during anticancer therapy in patients with pharyngeal cancer

BACKGROUND

The current study aimed to evaluate whether therapy-related changes occurred in brain metabolism at an earlier stage during the course of anticancer therapy.

METHODS

We recruited 14 non-diabetic male patients with newly diagnosed pharyngeal squamous cell carcinoma. We analyzed the patients' serial brain FDG PET/CT scans by SPM8 to establish whether any therapy-related changes had occurred in brain FDG metabolism, either during or after the course of therapy.

RESULTS

Decreased metabolism was noted during the anticancer therapy, displaying a symmetric pattern involving bilateral basal ganglia and bilateral occipital lobes. The decrease in FDG metabolism in these regions persisted after the anticancer therapy had terminated. However, relative recovery of the metabolism was noted in the bilateral occipital lobes, whereas further deterioration was noted in bilateral basal ganglia.

CONCLUSIONS

The current study revealed that unappreciable changes in brain metabolism can occur during the early course of anticancer therapy, and persist even after therapy has terminated. Although the exact mechanism remains unclear, these changes may be related to the systemic effects of chemotherapy or radiotherapy as well as subclinical cancer-related depressive or adjustment mood disorder.

Reversible posterior leukoencephalopathy syndrome induced by pazopanib

Background

The reversible posterior leukoencephalopathy syndrome is a clinical/radiological syndrome characterized by headache, seizures, impaired vision, acute hypertension, and typical magnetic resonance imaging findings. There are several reports in the literature that depict its occurrence in cancer patients. The list of common anticancer and supportive care drugs that predispose to reversible posterior leukoencephalopathy syndrome is expanding and includes not only a large number of chemotherapeutic agents but also an increased number of new targeted drugs, particularly angiogenesis inhibitors such as bevacizumab,sorefenib and sunitinib. Pazopanib is an oral tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor, platelet-derived growth factor receptor, and c-Kit which after a positive phase III randomized clinical trial in patients with advanced renal cell cancer received FDA approval for the treatment of advanced renal cell carcinoma. Until now no cases of reversible posterior leukoencephalopathy syndrome induced by pazopanib have been reported.

Case report

We present the case of a 40 years old female patient with heavily pre-treated metastatic renal cell carcinoma who received pazopanib as salvage treatment. After 21 days of pazopanib therapy the patient referred to the emergency department with epileptic seizure, impaired vision at both eyes and headache. MRI of the brain revealed subcortical oedema at the occipital and parietal lobes bilaterally. She was treated with anticonvulsants, i.v. administration of mannitol and antihypertensives and she recovered completely from her symptoms and was discharged on the tenth hospital day. A brain MRI performed 3 weeks after showed that the subcortical oedema had been subsided.

Conclusion

In conclusion this is the first case of pazopanib induced reversible posterior leukoencephalopathy syndrome. Although usually reversible, this syndrome is a serious and potentially life threatening adverse effect, if untreated, that should be considered by physicians treating metastatic renal cell carcinoma patients with pazopanib.

Neurologic complications of cancer drug therapies

PURPOSE OF REVIEW

The purpose of this article is to review neurologic complications associated with systemic anticancer therapies.

RECENT FINDINGS

Although neurologic complications from traditional chemotherapies are well described, most neurologists are less familiar with complications from agents that target specific pathways or receptors. This article also reviews the most common neurologic adverse effects associated with newer targeted agents.

SUMMARY

Patients with cancer are living longer because of earlier diagnoses and remarkable improvements in treatments. Unfortunately, both traditional chemotherapies and newer targeted agents are known to cause neurologic symptoms that can impact quality of life and play a role in limiting potential treatments. Acute, subacute, and chronic syndromes may affect the central or peripheral nervous system. Since treatments for therapy-induced neurotoxicity are limited, awareness of common neurologic complications is important to prevent permanent damage.

A phase I dose-escalation study of aflibercept administered in combination with pemetrexed and cisplatin in patients with advanced solid tumours

Background:

To evaluate the safety, pharmacokinetics (PKs), and pharmacodynamics of aflibercept, and to identify the recommended phase II dose (RP2D) of aflibercept in combination with pemetrexed and cisplatin.

Methods:

Aflibercept was administered at escalating doses of 2, 4, or 6 mg kg⁻¹ in combination with fixed doses of pemetrexed (500 mg m⁻²) plus cisplatin (75 mg m⁻²) every 3 weeks. Blood samples were collected for PK analyses. Serum antiaflibercept antibodies were quantified to assess their impact on systemic aflibercept concentrations.

Results:

Eighteen patients were enrolled. One patient dosed at 4 mg kg⁻¹ experienced grade 3 hypophosphatemia (dose-limiting toxicity; DLT), which prompted a cohort expansion. No further DLTs were observed in the 4 mg kg⁻¹ cohort or the 6 mg kg⁻¹ dose cohort. Most common adverse events (AEs) of all grades included (%): fatigue (89), anaemia (89), nausea (83), hyponatremia (78), and neutropenia (72). Grade ⩾3 AEs consistent with anti-vascular endothelial growth factor therapy included (%): hypertension (22), pulmonary embolism (11), and deep vein thrombosis (6). Five patients (28%) experienced mild neurocognitive disturbance. No episodes of reversible posterior leukoencephalopathy syndrome (RPLS) were noted.

Conclusion:

The results of this phase I study allowed further evaluation of the combination of aflibercept with pemetrexed and cisplatin in a phase II study. The RP2D of aflibercept was 6 mg kg⁻¹, to be administered intravenously every 3 weeks in combination with pemetrexed and cisplatin.

Central nervous system complications of cancer therapy

As more effective therapies prolong the survival of patients with cancer, therapy-related toxicities, particularly those affecting the central nervous system (CNS) become increasingly important. CNS complications can cause significant morbidity and can limit the dose or duration of otherwise effective treatments. Because effects on the CNS are disabling and often permanent and treatments remain limited, it is important that clinicians recognize the effects of cancer therapy on the CNS. Cytotoxic chemotherapy and radiation are well-known causes of neurotoxicity, but there is increasing recognition that novel therapies are also sources of adverse effects on the CNS. This review highlights the CNS complications that result from radiation, chemotherapy, and novel therapeutics.

Reversible posterior leukoencephalopathy induced by cancer chemotherapy

Reversible posterior leukoencephalopathy, defined by both clinical and neuroimaging findings, can affect children receiving chemotherapy. The syndrome is characterized by hypertension, alterations in mental status, seizures, hallucinations, and acute visual changes and is associated with abnormalities seen in magnetic resonance imaging of symmetric white matter lesions, especially in the parietal and occipital lobes. The etiology of reversible posterior leukoencephalopathy is as yet unknown. Presented here are four cases of reversible posterior leukoencephalopathy induced by chemotherapy, with a brief review of the literature and consideration of possible mechanisms. A diagnosis of reversible posterior leukoencephalopathy should be considered when patients receiving cancer chemotherapy suddenly develop hypertension followed by neurologic complications, especially if presenting with seizures.

Evidence for the role of bevacizumab in the treatment of advanced metastatic breast cancer: a review

Angiogenesis inhibitors may provide a new approach to the treatment of metastatic breast cancer. Bevacizumab is a monoclonal antibody against pathologic angiogenesis. A pivotal study (ECOG 2100) showed that bevacizumab in combination with paclitaxel increased progression-free survival for patients with metastatic breast cancer by 6 months. Subsequently, several clinical trials have shown that the combination of bevacizumab with a taxane can improve disease-free survival but does not prolong overall survival. While generally well tolerated, bevacizumab is potentially toxic for some patients who develop hypertension, proteinuria, bleeding, impaired wound healing, bowel perforation or thromboembolic events. Here, we review the current evidence for the use of bevacizumab in breast cancer and ongoing studies that address the questions of how to optimize regimens and schedules for the use of anti-angiogenic agents and the identification of those patients who would benefit the most from treatment with regimens that include antiangiogenic therapy.

Adverse effects of anticancer agents that target the VEGF pathway

Antiangiogenesis agents that target the VEGF/VEGF receptor pathway have become an important part of standard therapy in multiple cancer indications. With expanded clinical experience with this class of agents has come the increasing recognition of the diverse adverse effects related to disturbance of VEGF-dependent physiological functions and homeostasis in the cardiovascular and renal systems, as well as wound healing and tissue repair. Although most adverse effects of VEGF inhibitors are modest and manageable, some are associated with serious and life-threatening consequences, particularly in high-risk patients and in certain clinical settings. This Review examines the toxicity profiles of anti-VEGF antibodies and small-molecule inhibitors. The potential mechanisms of the adverse effects, risk factors, and the implications for selection of patients and management are discussed.